From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B2C24C433DB for ; Tue, 22 Dec 2020 20:02:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8377721D1B for ; Tue, 22 Dec 2020 20:02:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727235AbgLVUCG (ORCPT ); Tue, 22 Dec 2020 15:02:06 -0500 Received: from mail.kernel.org ([198.145.29.99]:44910 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727201AbgLVUCG (ORCPT ); Tue, 22 Dec 2020 15:02:06 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id DFB9120700; Tue, 22 Dec 2020 20:01:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1608667310; bh=rXPig3Y2BiXNEZi+1w0PI3jdh8Ii07tQ40TtSpXIZlQ=; h=Date:From:To:Subject:In-Reply-To:From; b=n4PJIavFFOdKcM4PaeR1OhWVk1SCIJ6K0nz4FK8seo+0ebIso9PIlRgXUZgOIYuf5 W32lVn18Ow9LNYiSORE5M0kGa9F/IXHcP7H8bFFCB9LOVKuE7YSXezWqzu0QQudGhe mQMpipd5L0UdZeBK3rlHAfq45CpAPuFfQozwDpM8= Date: Tue, 22 Dec 2020 12:01:49 -0800 From: Andrew Morton To: akpm@linux-foundation.org, andreyknvl@google.com, aryabinin@virtuozzo.com, Branislav.Rankov@arm.com, catalin.marinas@arm.com, dvyukov@google.com, elver@google.com, eugenis@google.com, glider@google.com, gor@linux.ibm.com, kevin.brodsky@arm.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org, vincenzo.frascino@arm.com, will.deacon@arm.com Subject: [patch 30/60] kasan, mm: untag page address in free_reserved_area Message-ID: <20201222200149.zhH1IPBra%akpm@linux-foundation.org> In-Reply-To: <20201222115844.d30aaef7df6f5b120d3e0c3d@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Vincenzo Frascino Subject: kasan, mm: untag page address in free_reserved_area free_reserved_area() memsets the pages belonging to a given memory area. As that memory hasn't been allocated via page_alloc, the KASAN tags that those pages have are 0x00. As the result the memset might result in a tag mismatch. Untag the address to avoid spurious faults. Link: https://lkml.kernel.org/r/ebef6425f4468d063e2f09c1b62ccbb2236b71d3.1606161801.git.andreyknvl@google.com Cc: Andrew Morton Signed-off-by: Vincenzo Frascino Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko Tested-by: Vincenzo Frascino Cc: Andrey Ryabinin Cc: Branislav Rankov Cc: Catalin Marinas Cc: Dmitry Vyukov Cc: Evgenii Stepanov Cc: Kevin Brodsky Cc: Marco Elver Cc: Vasily Gorbik Cc: Will Deacon Signed-off-by: Andrew Morton --- mm/page_alloc.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/mm/page_alloc.c~kasan-mm-untag-page-address-in-free_reserved_area +++ a/mm/page_alloc.c @@ -7671,6 +7671,11 @@ unsigned long free_reserved_area(void *s * alias for the memset(). */ direct_map_addr = page_address(page); + /* + * Perform a kasan-unchecked memset() since this memory + * has not been initialized. + */ + direct_map_addr = kasan_reset_tag(direct_map_addr); if ((unsigned int)poison <= 0xFF) memset(direct_map_addr, poison, PAGE_SIZE); _